Semiconductor manufacturing equipment, for example a photoresist coating apparatus, has a discharging gun for discharging a fluid having a certain level of viscosity. If a fluid having a viscosity such as a photoresist contains air bubbles during discharging, the fluid may cause a coating defect. As illustrated in FIG. 1, a conventional viscous fluid discharging apparatus includes storage container 1 for containing and storing a viscous fluid, viscous fluid pump 2 for supplying the viscous fluid from storage container 1, viscous fluid filter 3 connected to an outlet of viscous fluid pump 2 for filtering off impurity materials and air bubbles contained in the viscous fluid, and viscous fluid discharging mechanism 4 for supplying the viscous fluid to relevant regions.
Particularly, viscous fluid discharging mechanism 4 typically has a sectional constitution as illustrated in FIG. 2. Viscous fluid discharging mechanism 4 includes a temperature adjusting means having path 21 for temperature adjusting fluid 22 on the outside of discharging gun 20, for maintaining the viscous fluid at a certain temperature range when it is discharging from discharging gun 20.
For example, to look into a process for spreading photoresist onto a substrate, if a carrier containing a wafer is loaded to a wafer supplying portion, then the wafer automatically is moved to a photoresist coating section, with the result that the wafer is mounted on a vacuum chuck. Consequently, the wafer is rotated, while the viscous fluid supplying pump is activated. Sometimes, the pump is activated in a state with the wafer being stopped without rotation. When the viscous fluid supplying pump is activated, the viscous fluid is sucked up from the viscous fluid storing container to pass through the viscous fluid supplying pump, the viscous fluid filter and the final viscous fluid discharging mechanism to be discharged so as to coat the wafer.
In this process, when the viscous fluid together with residue air bubbles passes through the viscous fluid supplying pump, most of the air bubbles are removed by the viscous fluid filter. However, part of air bubbles 25 pass through the viscous fluid filter, or air can be introduced into the viscous fluid due to the fact that the sealing of the joining portion of the viscous fluid discharging apparatus is not perfect. In this case, there is no further means for removing the air bubbles, and, therefore, the viscous fluid containing the air bubbles is discharged to the wafer, with the result that coating defects are produced.